Electrode winding element for non-aqueous electrolyte rechareable battery, non-aqueous electrolyte rechargeable lithium battery including same, method of preparing same

ABSTRACT

An electrode wound element for a non-aqueous electrolyte rechargeable battery includes a belt-shaped positive electrode; a belt-shaped negative electrode; a belt-shaped porous layer between the belt-shaped positive electrode and the belt-shaped negative electrode; and an adhesive layer formed on the surface of the belt-shaped porous layer, wherein the adhesive layer includes a fluorine resin-containing particulate and a binder for an adhesive layer supporting the fluorine resin-containing particulate, the binder comprising at least one of an ionic non-water-soluble binder, a non-ionic water-soluble binder, a non-ionic non-water-soluble binder and an ionic water-soluble binder.

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. This application claims priority to and the benefit ofJapanese Patent Application No. 2014-258189 filed in the Japanese PatentOffice on Dec. 22, 2014, and Korean Patent Application No.10-2015-0117519 filed in the Korean Intellectual Property Office on Aug.20, 2015. Each of the aforementioned applications is incorporated byreference herein in its entirety, and each is hereby expressly made apart of this specification.

BACKGROUND

1. Field

An electrode wound element for a non-aqueous electrolyte rechargeablebattery, a non-aqueous electrolyte rechargeable battery including thesame, and a method of preparing the electrode wound element for anon-aqueous electrolyte rechargeable battery are provided.

2. Description of the Related Art

Research on a polyvinylidene fluoride (PVDF)-based fluorine resin as amatrix polymer of a gel electrolyte for a rechargeable lithium ionbattery has been actively made. For example, technology for forming aporous layer made of the PVDF-based fluorine resin on the surface of aseparator is widely known. In this technology, the porous layer is, forexample, formed on the surface of the separator in the following method.

A first method includes preparing a slurry by dissolving a fluorineresin in an organic solvent such as NMP (N-methyl pyrrolidone), dimethylacetamide, acetone, or the like, coating the slurry on a separator or anelectrode, and phase-separating the fluorine resin by using a poorsolvent such as water, methanol, tripropylene glycol, or the like orvapor thereof to form a porous coating layer in which the fluorine resinis made porous.

A second method includes preparing a thermal slurry by dissolving afluorine resin in a heating electrolytic solution using a solvent suchas dimethyl carbonate, propylene carbonate, ethylene carbonate, or thelike to prepare heated slurry, coating the heated slurry on a separatoror an electrode to prepare a coating layer, cooling down the coatinglayer, and transferring the fluorine resin into a gel (a porous layerswollen by an electrolyte solution).

However, the separator having the PVDF porous layer on the surface inthe above method has insufficient slipperiness when compared to aseparator having no porous layer and easily becomes electrostatic andthus is difficult to handle in a preparing process. Specifically, whenthe separator is overlapped with belt-shaped positive and negativeelectrodes for a wound element, the wound element becomes deformed dueto the insufficient mutual slipperiness of the separator. When the woundelement is deformed, the wound element is difficult to be inserted intoa case. In addition, a non-aqueous electrolyte rechargeable batteryusing this deformed wound element may have an insufficient cycle-life.

Furthermore, the separator having the polyvinylidene fluoride porouslayer on the surface according to the aforementioned method hasinsufficient adherence to an electrode, and particularly, theinsufficient adherence problem tends to be severe when the separatorincludes a heat resistance filler to improve heat resistance. When theseparator has insufficient adherence to each electrode, a wound elementmay has a problem of easy expansion (so-called a problem of cycleexpansion) as charge and discharge proceed.

In contrast, Japanese Patent Laid-Open Publication No. Hei. 10-110052,Japanese Patent Laid-Open Publication No. 2012-190784, Japanese PatentPublication No. 2010-538173, and Japanese Patent Laid-Open PublicationNo. 2011-204627, for example, disclose technology for using fluorineresin particles or ceramic particles. Japanese Patent Laid-OpenPublication No. Hei. 10-110052 discloses a method of protruding a partof the fluorine resin particles out of a porous film separator. JapanesePatent Laid-Open Publication No. 2012-190784 discloses a method ofincluding the ceramic particles inside a separator. Japanese PatentLaid-Open Publication No. 2010-538173 discloses a method of charging apart of micropores in a non-woven fabric with the fluorine resinparticles. Japanese Patent Laid-Open Publication No. 2011-204627discloses a method of preparing a negative electrode by using aqueousslurry in which a polymer complex of a fluorine resin and a polymerhaving an oxygen-containing functional group is dispersed. However,these methods do not solve the aforementioned problem at all.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One embodiment provides an electrode wound element for a non-aqueouselectrolyte rechargeable battery capable of improving handling propertyof a separator during the preparation, being suppressed fromdeformation, and improving adherence of the separator to each electrode.

Another embodiment provides a non-aqueous electrolyte rechargeablebattery including the electrode wound element.

Yet another embodiment provides a method of preparing an electrode woundelement for a non-aqueous electrolyte rechargeable battery.

According to one embodiment, an electrode wound element for anon-aqueous electrolyte rechargeable battery includes a belt-shapedpositive electrode; a belt-shaped negative electrode; a belt-shapedporous layer between the belt-shaped positive electrode and thebelt-shaped negative electrode; and an adhesive layer formed on thesurface of the belt-shaped porous layer, wherein the adhesive layerincludes a fluorine resin-containing particulate and a binder for anadhesive layer supporting the fluorine resin-containing particulate andhaving a total volume which is less than that of the fluorineresin-containing particulate, the binder for an adhesive layer includesat least one selected from an ionic non-water-soluble binder, anon-ionic water-soluble binder, a non-ionic non-water-soluble binder andan ionic water-soluble binder, provided that when the binder for theadhesive layer includes an ionic water-soluble binder, the binder for anadhesive layer further includes at least one selected from the ionicnon-water-soluble binder, the non-ionic water-soluble binder and thenon-ionic non-water-soluble binder, and a content of the ionicwater-soluble binder is about 2 wt % or less based on the weight of thefluorine resin-containing particulate.

In one embodiment, the binder for the adhesive layer may include atleast one selected from an ionic non-water-soluble binder and anon-ionic water-soluble binder.

In one embodiment, the ionic non-water-soluble binder may include atleast one selected from a carboxylic acid-modified acrylic acid ester, apolyolefin ionomer, and a carboxylic acid-modified styrene-butadienecopolymer.

In one embodiment, the non-ionic water-soluble binder may include atleast one selected from poly-N-vinyl acetamide (PNVA), polyvinyl alcohol(PVA), hydroxyethyl cellulose (HEC), methyl cellulose,polyvinylpyrrolidone (PVP), and polyoxyethylene.

In one embodiment, the belt-shaped negative electrode may include anegative active material layer including a negative active material anda fluorine resin-containing particulate, and the adhesive layer may beattached to the negative active material layer.

In one embodiment, the fluorine resin-containing particulate may be aspherical shape particle.

In one embodiment, the fluorine resin may include polyvinylidenefluoride.

According to one embodiment, a non-aqueous electrolyte rechargeablebattery including the electrode wound element for a non-aqueouselectrolyte rechargeable battery is provided.

According to one embodiment, a method of preparing an electrode woundelement for a non-aqueous electrolyte rechargeable battery includes:coating and drying aqueous slurry including a fluorine resin-containingparticulate; and a binder for an adhesive layer supporting the fluorineresin-containing particulate and having a total volume which is lessthan that of the fluorine resin-containing particulate on the surface ofa belt-shaped porous layer, wherein the binder for an adhesive layerincludes at least one selected from an ionic non-water-soluble binder, anon-ionic water-soluble binder, a non-ionic non-water-soluble binder andan ionic water-soluble binder or the binder for an adhesive layerincludes an ionic water-soluble binder and at least one selected from anionic non-water-soluble binder, a non-ionic water-soluble binder and anon-ionic non-water-soluble binder, and a content of the ionicwater-soluble binder is about 2 wt % or less based on the weight of thefluorine resin-containing particulate.

According to one embodiment, the wound element may improve handlingproperties of a separator and be suppressed from deformation. Theadherence of the adhesive layer of the separator to each electrode maybe improved, and also, the cycle expansion of the wound element may beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing the schematic structure of arechargeable lithium ion battery according to one embodiment.

FIG. 2 is a cross-sectional view showing the schematic structure of anelectrode stack structure according to one embodiment.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Hereinafter, the present invention is described in detail.

According to one embodiment, an electrode wound element for anon-aqueous electrolyte rechargeable battery includes a belt-shapedpositive electrode; a belt-shaped negative electrode; a belt-shapedporous layer between the belt-shaped positive electrode and thebelt-shaped negative electrode; and an adhesive layer formed on thesurface of the belt-shaped porous layer, wherein the adhesive layerincludes a fluorine resin-containing particulate and a binder for anadhesive layer supporting the fluorine resin-containing particulate andhaving a total volume which is that of the fluorine resin-containingparticulate, the binder for an adhesive layer includes at least oneselected from an ionic non-water-soluble binder, a non-ionicwater-soluble binder, a non-ionic non-water-soluble binder and an ionicwater-soluble binder, provided that when the binder for the adhesivelayer includes an ionic water-soluble binder, the binder for an adhesivelayer further includes at least one selected from the ionicnon-water-soluble binder, the non-ionic water-soluble binder and thenon-ionic non-water-soluble binder, and a content of the ionicwater-soluble binder is about 2 wt % or less based on the weight of thefluorine resin-containing particulate.

The adhesive layer includes the fluorine resin-containing particulateand the binder for an adhesive layer supporting the fluorineresin-containing particulate and having a total volume which is lessthan that of the fluorine resin-containing particulate, and thus mayimprove handling property of the separator. In addition, the woundelement may be suppressed from deformation.

Furthermore, the binder for an adhesive layer is included in the abovestructure and adherence of the adhesive layer to each electrode may beimproved and as a result, cycle expansion is improved.

The binder for the adhesive layer may include at least one selected froman ionic non-water-soluble binder and a non-ionic water-soluble binder.In connection therewith, the adherence of the adhesive layer to eachelectrode is improved, and as a result, the cycle expansion of the woundelement may be improved.

The ionic non-water-soluble binder may include at least one selectedfrom a carboxylic acid-modified acrylic acid ester, a polyolefinionomer, and a carboxylic acid-modified styrene-butadiene copolymer. Inconnection therewith, the adherence of the adhesive layer to eachelectrode is improved, and as a result, the cycle expansion of the woundelement may be improved.

The non-ionic water-soluble binder may include at least one selectedfrom poly-N-vinyl acetamide (PNVA), polyvinyl alcohol (PVA),hydroxyethyl cellulose (HEC), methyl cellulose, polyvinylpyrrolidone(PVP), and polyoxyethylene. In connection therewith, the adherence ofthe adhesive layer to each electrode is improved, and as a result, thecycle expansion of the wound element may be improved.

The belt-shaped negative electrode includes a negative active materiallayer including a negative active material and a fluorineresin-containing particulate, and the adhesive layer may be adhered tothe negative active material layer. The deformation of the wound elementmay be further improved, and in addition, the adherence of the adhesivelayer to each electrode is improved, and as a result, the cycleexpansion of the wound element may be improved.

The fluorine resin-containing particulate may have a spherically shapedparticle. In connection therewith, the handling property of theseparator and the deformation of the wound element may be furtherimproved. In addition, the adherence of the adhesive layer to eachelectrode is improved, and as a result, the cycle expansion the woundelement may be improved.

The fluorine resin may include polyvinylidene fluoride. Herein, thehandling property of the separator and the deformation of the woundelement may be further improved. In addition, the adherence of theadhesive layer to each electrode is improved, and as a result, the cycleexpansion of the wound element may be improved.

Another embodiment provides a non-aqueous electrolyte rechargeablebattery including the electrode wound element for a non-aqueouselectrolyte rechargeable battery.

Yet another embodiment provides a method of preparing an electrode woundelement for a non-aqueous electrolyte rechargeable battery includescoating and drying aqueous slurry including a fluorine resin-containingparticulate; and a binder for an adhesive layer supporting the fluorineresin-containing particulate and having a total volume which is lessthan that of the fluorine resin-containing particulate on the surface ofa belt-shaped porous layer, wherein the binder for an adhesive layerincludes at least one selected from an ionic non-water-soluble binder, anon-ionic water-soluble binder, a non-ionic non-water-soluble binder andan ionic water-soluble binder or the binder for an adhesive layerincludes an ionic water-soluble binder and at least one selected from anionic non-water-soluble binder, a non-ionic water-soluble binder and anon-ionic non-water-soluble binder, and a content of the ionicwater-soluble binder is about 2 wt % or less based on the weight of thefluorine resin-containing particulate.

The preparing method may improve the handling properties of theseparator and the deformation of the wound element.

Hereinafter, referring to the drawings, one exemplary embodiment isillustrated in detail. On the other hand, constituent elementssubstantially having the same functional structure in the presentspecification and drawing are assigned by the same numeral and will notbe repetitively illustrated.

1. Structure of Rechargeable Lithium Ion Battery Entire Structure ofRechargeable Lithium Ion Battery

First, referring to FIGS. 1 and 2, a rechargeable lithium ion batteryaccording to one embodiment is illustrated. FIG. 1 provides a plane viewshowing a wound element 100 and an enlarged view regarding the region Aof the wound element 100. FIG. 2 provides a plane view showing anelectrode stack structure 100 a in which a positive electrode, anegative electrode, and two sheets of separator are stacked and anenlarged view showing the region A of the electrode stack structure 100a.

The rechargeable lithium ion battery includes a wound element 100, anon-aqueous electrolyte solution, and an exterior material. The woundelement 100 is obtained by winding the electrode stack structure 100 aobtained by sequentially stacking a belt-shaped negative electrode 10, abelt-shaped separator 20, a belt-shaped positive electrode 30, and abelt-shaped separator 20 in a length direction and compressing the woundelectrode stack structure 100 a in an arrow direction B.

Structure of Negative Electrode

The belt-shaped negative electrode 10 includes a negative currentcollector 10 b and negative active material layers 10 a formed on thenegative current collector 10 b.

The belt-shaped negative electrode 10 may be an aqueous negativeelectrode. That is, the wound element 100 and the rechargeable lithiumion battery according to the present embodiment may include an aqueousnegative electrode.

Specifically, the negative active material layer 10 a includes anegative active material, a thickener, and a binder.

The negative active material layer 10 a may include a negative activematerial, a thickener and a binder. The negative active material of thenegative active material layer 10 a may include is not particularlylimited as long as it may be alloyed with lithium or reversiblyintercalated and deintercalated with lithium. For example, the negativeactive material may include a metal such as lithium, indium (In), tin(Sn), aluminum (Al), silicon (Si) or the like, alloys or oxides thereof;transition metal oxide such as Li_(4/3)Ti_(5/3)O₄, SnO, or the like; acarbon material such as artificial graphite, natural graphite, a mixtureof artificial graphite and natural graphite, natural graphite coatedwith artificial graphite, a hard carbon, graphite carbon fiber,resin-fired carbon, thermal decomposition vapor grown carbon, coke,mesocarbon microbeads (MCMB), a furfuryl alcohol resin-fired carbon,polyacene, a pitch-based carbon fiber, or the like; or the like.

These may be used singularly or in a mixture of two or more. Among them,graphite-based materials such as artificial graphite, natural graphite,a mixture of artificial graphite and natural graphite, natural graphitecoated with artificial graphite, hard carbon, a graphite carbon fibermay be used as a main material.

The thickener may adjust a viscosity of negative active material layerslurry to be suitably coated and simultaneously may act as a binder inthe negative active material layer 10 a. The thickener may be awater-soluble polymer, for example a cellulose-based polymer, apolyacrylic acid-based polymer, polyvinyl alcohol, polyethylene oxide,or the like. The cellulose-based polymer may be, for example a metalsalt of carboxymethyl cellulose (CMC), an alkali metal salt or anammonium salt, a cellulose derivative such as methyl cellulose, ethylcellulose, hydroxy alkyl cellulose, or the like.

The thickener may be polyvinylpyrrolidone; starch; phosphoric acidstarch; casein; each kind of modified starch; chitin; a chitosanderivative, or the like. These may be used singularly or in a mixture oftwo or more. Among them, the cellulose-based polymer may be used, andfor example, and an alkali metal salt of carboxymethyl cellulose may beused.

The binder attaches negative active materials to each other. The bindermay be any binder for an aqueous negative electrode without particularlimitation. Examples of the binder may be a particulate of anelastomer-based polymer. The elastomer-based polymer may be SBR (styrenebutadiene rubber), BR (butadiene rubber), NBR (nitrilebutadiene rubber),NR (natural rubber), IR (isoprene rubber), EPDM(ethylene-propylene-diene terpolymer), CR (chloroprene rubber), CSM(chloro sulfonated polyethylene), acrylic acid ester, a copolymer ofmethacrylic acid ester, and a partly or wholly hydrogenated polymerthereof, an acrylic acid ester-based copolymer, or the like. Inaddition, in order to improve the binding properties, it may be modifiedwith a monomer having a polar functional group such as a carboxylic acidgroup, a sulfonic acid group, a phosphoric acid group, a hydroxy group,or the like. Furthermore, the negative active material layer 10 a mayinclude a post-described fluorine resin-containing particulate as abinder. The fluorine resin-containing particulate is added to slurry ina powder form and dispersed therein or in an aqueous dispersion form.

The slurry for forming the negative active material layer 10 a may usewater as a solvent.

The amount ratio of a thickener and a binder in the negative activematerial layer is not particularly limited but may be any ratioapplicable to a negative active material layer for a rechargeablelithium ion battery.

The negative current collector 10 b may include any materials as long asbeing a conductor, and examples thereof may include copper, stainlesssteel, nickel plating steel, or the like. A negative terminal may beconnected to the negative current collector 10 b.

The belt-shaped negative electrode 10 may be, for example, prepared inthe following method. In other words, negative active material layerslurry (aqueous slurry) is prepared by dispersing a negative activematerial layer material into water and then, coated on a currentcollector to form a coating layer.

Subsequently, the coating layer is dried. Herein, a fluorine resinparticulate and an elastomer-based polymer particulate in the negativeactive material layer slurry are dispersed in the negative activematerial layer 10 a. Subsequently, the dried coating layer is compressedwith the negative current collector 10 b, preparing the belt-shapednegative electrode 10.

A belt-shaped porous layer 20 c is not particularly limited but may beany separator used for a rechargeable lithium ion battery.

As for the belt-shaped porous layer 20 c, a porous layer or a non-wovenfabric showing excellent high rate discharge performance or the like maybe used alone or as a combination. The belt-shaped porous layer 20 c mayinclude a resin, for example a polyolefin-based resin such aspolyethylene and polypropylene, a polyester-based resin such aspolyethylene terephthalate, polybutylene terephthalate, polyvinylidenefluoride, a vinylidene fluoride (VDF)-hexafluoro propylene (HFP)copolymer, a vinylidene fluoride-perfluoro vinylether copolymer, avinylidene fluoride-tetrafluoroethylene copolymer, a vinylidenefluoride-trifluoroethylene copolymer, a vinylidenefluoride-fluoroethylene copolymer, a vinylidene fluoride-hexafluoroacetone copolymer, a vinylidene fluoride-ethylene copolymer, avinylidene fluoride-propylene copolymer, a vinylidene fluoride-trifluoropropylene copolymer, a vinylidenefluoride-tetrafluoroethylene-hexafluoro propylene copolymer, avinylidene fluoride-ethylene-tetrafluoroethylene copolymer, or the like.

An adhesive layer 20 a includes the aforementioned fluorineresin-containing particulate 20 b-1 and the binder 20 b-2 for anadhesive layer and binds the belt-shaped separator 20 with thebelt-shaped negative electrode 10 and the belt-shaped positive electrode30. In FIG. 1, the adhesive layer 20 a is formed on both sides of thebelt-shaped separator 20 but may be formed on at least one surfacethereof.

The fluorine resin-containing particulate 20 b-1 includes a fluorineresin. Example of the fluorine resin including the fluorineresin-containing particulate 20 b-1 may include, polyvinylidenefluoride, a copolymer including polyvinylidene fluoride, or the like.The copolymer including the polyvinylidene fluoride may be a copolymerof vinylidene fluoride (VDF) and hexafluoro propylene (HFP), a copolymerof vinylidene fluoride (VDF) and tetrafluoroethylene (TFE), or the like.As for the fluorine resin, the copolymer modified with a polar groupsuch as carboxylic acid or the like may be used.

The particle diameter of the fluorine resin-containing particulate 20b-1 (when the fluorine resin-containing particulate 20 b-1 is referredto as a spherical shape) has no particular limit but may be any sizedispersible in the negative active material layer 10 a. For example, thefluorine resin-containing particulate 20 b-1 may have an averageparticle diameter (an arithmetic average of particle diameters) in arange of about 80 nm to about 500 nm. The average particle diameter ofthe fluorine resin-containing particulate 20 b-1 may be for examplemeasured in a laser diffractometry method. Specifically, the laserdiffractometry method is used to measure the particle distribution ofthe fluorine resin-containing particulate 20 b-1, and this particledistribution is used to calculate the arithmetic average of particlediameters.

On the other hand, the fluorine resin-containing particulate 20 b-1 maybe variously processed, for example, combined with another resin, unlessan effect according to one exemplary embodiment is deteriorated. Forexample, the fluorine resin-containing particulate 20 b-1 may becombined with an acrylic resin. The fluorine resin-containingparticulate 20 b-1 may have an IPN (inter-penetrating network polymer)structure.

The fluorine resin-containing particulate 20 b-1 may be for exampleprepared by emulsion-polymerizing a monomer including a fluorine resin(for example, vinylidene fluoride). In addition, the fluorineresin-containing particulate 20 b-1 may be prepared bysuspension-polymerizing a monomer including a fluorine resin andgrinding a coarse particle obtained therefrom.

The fluorine resin-containing particulate 20 b-1 may appropriately be aspherical shape particle. The spherically-shaped fluorineresin-containing particulate 20 b-1 may be for example prepared in theemulsion polymerization method. In addition, the fluorineresin-containing particulate 20 b-1 may be for example examined with SEM(a scanning electron microscope).

A binder 20 b-2 for the adhesive layer 20 a may support the fluorineresin-containing particulate 20 b-1 in the adhesive layer 20 a. Thetotal volume of the binder 20 b-2 in the adhesive layer 20 a is smallerthan the total volume of the fluorine resin-containing particulate 20b-1 in the adhesive layer 20 a. Specifically, the total volume of thefluorine resin-containing particulate 20 b-1/the total volume of thebinder 20 b-2 for the adhesive layer may be in a range of 2 to 20.

When the adhesive layer 20 a includes the fluorine resin-containingparticulate 20 b-1 and the binder 20 b-2 for an adhesive layer in theabove volume ratio, the handling property of the belt-shaped separator20 during the preparation may be improved. Specifically, theslipperiness of the belt-shaped separator 20 is improved, and thedeformation of the wound element 100 may be suppressed. As a result,cycle-life of a battery may be improved.

The binder 20 b-2 for the adhesive layer may include at least oneselected from an ionic non-water-soluble binder, a non-ionicwater-soluble binder, and a non-ionic non-water-soluble binder.According to another embodiment, the binder 20 b-2 for the adhesivelayer may include at least one selected from an ionic non-water-solublebinder and a non-ionic water-soluble binder.

In one embodiment, the binder 20 b-2 for the adhesive layer may furtherinclude an ionic water-soluble binder. Herein, the content of the ionicwater-soluble binder may be less than or equal to about 2 wt % (based onthe mass of fluorine resin-containing particulate). Specifically, theionic water-soluble binder may be included in an amount of less than orequal to about 1.0 wt %.

When the ionic water-soluble binder is included in an amount of greaterthan about 2 wt %, the adherence of the adhesive layer 20 a may bedeteriorated. The adherence of the adhesive layer 20 a may be realized,as the polar groups that the fluorine resin-containing particulate 20b-1, the ionic non-water-soluble binder, or the like included in theadhesive layer 20 a have are oriented in a particular direction on theinterface with an electrode (particularly, a negative electrode), andwhen the content of the ionic water-soluble binder is larger than about2 wt %, the ionic water-soluble binder uniformly distributed in coatingand drying processes may have negative influence on the orientation ofthe polar groups on the surface of the electrode and as a result,deteriorate the adherence of the adhesive layer 20 a.

In one embodiment, when the binder 20 b-2 for the adhesive layerincludes a non-ionic water-soluble binder, at least one selected from anionic non-water-soluble binder, and a non-ionic non-water-solublebinder, the content of the non-ionic water-soluble binder (based on thetotal weight of the binder 20 b-2 for an adhesive layer) may be lessthan or equal to about 50 wt %. When the non-ionic water-soluble binderis included in an amount of less than or equal to about 50 wt %, aseparator having satisfactory ion permeability may be obtained withoutdeteriorating porosity of a porous layer during formation of an adhesivelayer accompanied with drying and coating.

The ionic non-water-soluble binder is not particularly limited. Examplesof the ionic non-water-soluble binder may be carboxylic acid-modifiedacrylic acid ester, a polyolefin ionomer and a carboxylic acid-modifiedstyrene-butadiene copolymer. The ionic non-water-soluble binder may beby itself or in a mixture thereof.

The non-ionic water-soluble binder is not particularly limited. Examplesof the non-ionic water-soluble binder may be poly-N-vinyl acetamide(PNVA), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP),hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose,hydroxypropyl guar gum, locust bean gum, and polyoxyethylene. Thenon-ionic water-soluble binder may be by itself or in a mixture thereof.

The non-ionic non-water-soluble binder is not particularly limited.Examples of the non-ionic non-water-soluble binder may be a polybutylacrylate aqueous dispersed material or the like obtained byemulsion-polymerizing a radical polymerizable monomer such as butylacrylate or the like, an anion-based surfactant such as sodium laurylsulfate or the like, and a water-soluble initiator such as potassiumpersulfate. The non-ionic non-water-soluble binder may be obtained byappropriately copolymerizing a monomer including a hydroxy group such asacrylic acid-2-hydroxyethyl to improve dispersion stability in water. Inaddition, the non-ionic non-water-soluble binder may be non-modifiedpoly methylmethacrylate. The non-ionic non-water-soluble binder may beone or more than two selected among these materials.

The ionic water-soluble binder is not particularly limited. Examples ofthe ionic water-soluble binder may be poly acrylic acid, carboxymethylcellulose (CMC), a styrene-maleic acid copolymer, an isobutylene-maleicacid copolymer, an N-vinyl acrylamide-acrylic acid copolymer, an alkalimetal salt thereof, an ammonium salt thereof, or the like. The ionicwater-soluble binder may be one or more than two selected among thesematerials.

According to one embodiment, the binder for the adhesive layer has theabove structure and thus may improve the adherence of the adhesive layer20 a to each electrode, particularly, the negative electrode 10. Inaddition, cycle expansion may be suppressed.

The adhesive layer 20 a may also include a thickener to applyappropriate viscosity during coating. In addition, the adhesive layer 20a may further include a heat resistance filler particle to adjustporosity and obtain thermal stability.

The heat resistance filler particle has no particular limit but may, forexample, include a heat resistance organic filler particle, a heatresistance inorganic filler particle, or a mixture thereof. When theheat resistance organic filler particle and the heat resistanceinorganic filler particle are mixed, there is no particular limit totheir mixing ratio.

In one embodiment, the heat resistance filler physically suppressesthermal contraction of a porous layer and has insufficient mobility inthe adhesive layer. Accordingly, when the heat resistance fillerparticle is included in the porous layer, the porous layer almost doesnot move, even though a wound element is pushed down under a lowerpressure than when an electrode is compressed, and accordingly, asufficient adhesive interface on the porous layer is not formed, and theporous layer is not sufficiently adhered to each electrode. In otherwords, the separator has insufficient adherence to each electrode.

The heat resistance organic filler particle has a shape close to asphere and simultaneously a satisfactory surface slipperiness and thusmay be easily dispersed in the adhesive layer 20 a when the woundelement 100 is pushed down, and accordingly, an adhesive interfacebetween the adhesive layer 20 a and each electrode 10 and 20 may beeasily enlarged even under a low pressure when the wound element 100 ispushed down. Accordingly, the heat resistance filler particle includedin the adhesive layer 20 a may be preferably the heat resistance organicfiller.

The heat resistance organic filler particle may be, for example,cross-linked polystyrene (cross-linked PS), cross-linked polymethylmethacrylate (cross-linked PMMA), a silicone resin, cured epoxy,polyether sulfone, polyamideimide, polyimide, a melamine resin, apolyphenylenesulfide resin particulate, or the like. The heat resistanceorganic filler particle may be one or more than two selected from thesematerials.

The heat resistance inorganic filler particle may be specifically aceramic particle and more specifically a metal oxide particle. The metaloxide particle may be, for example, particulates of alumina, boehmite,titania, zirconia, magnesia, zincoxide, hydroxide aluminum, magnesiumhydroxide, or the like.

The average particle diameter of the heat resistance filler particle maybe less than or equal to ⅔ of the thickness of the adhesive layer 20 a.The average particle diameter of the heat resistance filler particleindicates an accumulated volume of 50% (D50) measured in a laserdiffraction method. The content of the heat resistance filler particlehas no particular limit, as far as an effect according to an exemplaryembodiment is obtained but may be less than or equal to about 80 wt %based on the total weight of the adhesive layer 20 a.

The adhesive layer 20 a may be prepared in the following method.

A material for the adhesive layer 20 a is dissolved in and dispersed inwater to prepare adhesive layer mix slurry (aqueous slurry).Subsequently, this adhesive layer mix slurry is coated on at least onesurface of the belt-shaped porous layer 20 c out of both sides to form acoating layer. Then, this coating layer is dried. Through this process,the adhesive layer 20 a is formed.

The belt-shaped positive electrode 30 may include a positive electrodecurrent collector 30 b and a positive active material layer 30 a formedon both surfaces of the positive electrode current collector 30 b. Thepositive active material layer 30 a may include at least a positiveactive material and further a conductive agent and a binder.

The positive active material may include any material reversiblyintercalating and deintercalating lithium ions without any particularlimit but, for example, lithium cobalt oxide (LCO), lithium nickeloxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide(hereinafter, referred to be “NCA”), lithium nickel cobalt manganeseoxide (hereinafter, referred to be “NCM”), lithium manganese oxide,lithium iron phosphate, nickel sulfate, copper sulfate, sulfur, ironoxide, vanadium oxide, or the like. These positive active materials maybe used alone or as a mixture of more than two. The NCA and NCMcorrespond to a lithium salt of transition metal oxide having a layeredrock salt structure.

Particularly, the positive active material may be a lithium salt oftransition metal oxide having a layered rock salt structure among theabove materials. The NCA or NCM, the lithium salt of transition metaloxide having a layered rock salt structure may be, for example, alithium salt of ternary transition metal oxide represented byLi_(1-x-y-z)Ni_(x)Co_(y)Al_(z)O₂ (NCA) orLi_(1-x-y-z)Ni_(x)Co_(y)Mn_(z)O₂ (NCM) (wherein, 0<x<1, 0<y<1, 0<z<1,simultaneously x+y+z<1).

The conductive agent may be, for example, carbon black such as ketjenblack, acetylene black, or the like, natural graphite, artificialgraphite, or the like but has no particular limit if conductivity of apositive electrode is increased.

The binder bonds the positive active material itself and also, thepositive active material with the positive electrode current collector30 b. The binder has no particular limit in its kind but includes anybinder used in a conventional positive active material layer for arechargeable lithium ion battery. For example, the binder may bepolyvinylidene fluoride, a vinylidene fluoride (VDF)-hexafluoropropylene (HFP) copolymer, a vinylidene fluoride-perfluoro vinylethercopolymer, a vinylidene fluoride-tetrafluoroethylene copolymer, avinylidene fluoride-trifluoroethylene copolymer, an ethylenepropylenediene terpolymer, a styrene butadiene rubber, an acrylonitrile butadienerubber, fluororubber, polyvinyl acetate, polymethyl methacrylate,polyethylene, cellulose nitrate, but the binder may not be particularlylimited if it binds the positive active material and the conductiveagent on the current collector 21.

The positive electrode current collector 30 b may include any conductor,for example, aluminum, stainless steel, nickel plating steel or thelike. The positive electrode current collector 30 b may be connectedwith a positive terminal.

The belt-shaped positive electrode 30 may be prepared, for example, inthe following method.

A positive active material layer material is dispersed in an organicsolvent or water to prepare positive active material layer slurry, andthen, the positive active material layer slurry is coated on a currentcollector to form a coating layer. Subsequently, the coating layer isdried and compressed with a positive electrode current collector 30 b,preparing the belt-shaped positive electrode 30. The organic solvent maybe N-methylpyrrolidone but is not limited thereto.

The electrode stack structure 100 a is prepared by sequentially stackingthe belt-shaped negative electrode 10, the belt-shaped separator 20, thebelt-shaped positive electrode 30, and the belt-shaped separator 20.Accordingly, since the belt-shaped separator 20 is disposed on onesurface of the electrode stack structure 100 a, and the belt-shapednegative electrode 10 is disposed on the other surface thereof, the onesurface of the electrode stack structure 100 a (i.e., the belt-shapedseparator 20) contacts the other surface of the electrode stackstructure 100 a (i.e., the belt-shaped negative electrode 10) when theelectrode stack structure 100 a is wound.

The non-aqueous electrolyte is obtained by dissolving an electrolyticsalt in an organic solvent. The electrolytic salt is not particularlylimited, for example, a lithium salt. The lithium salt may be, forexample, an inorganic ion salt including lithium (Li), sodium (Na) orpotassium (K) such as LiClO₄, LiBF₄, LiAsF₆, LiPF₆,LiPF_(6-x)(C_(n)F_(2n+1))_(x) (1<x<6, n=1 or 2), LiSCN, LiBr, LiI,Li₂SO₄, Li₂B₁₀Cl₁₀, NaClO₄, NaI, NaSCN, NaBr, KClO₄, KSCN or the like,an organic ion salt such as LiCF₃SO₃, LiN(CF₃SO₂)₂, LiN(C₂F₅SO₂)₂,LiN(CF₃SO₂)(C₄F₉SO₂), LiC(CF₃SO₂)₃, LiC(C₂F₅SO₂)₃, (CH₃)₄NBF₄,(CH₃)₄NBr, (C₂H₅)₄NClO₄, (C₂H₅)₄NI, (C₃H₇)₄NBr, (n-C₄H₉)₄NClO₄,(n-C₄H₉)₄NI, (C₂H₅)₄N-maleate, (C₂H₅)₄N-benzoate, (C₂H₅)₄N-phthalate,lithium stearyl sulfate, lithium octyl sulfate, lithium dodecylbenzenesulphonate. These may be used by themselves or in a mixture of two ormore.

The concentration of the electrolytic salt may be the same as that of anon-aqueous electrolyte used in a conventional rechargeable lithiumbattery, and is not particularly limited. In one embodiment, anelectrolyte solution including an appropriate lithium compound(electrolytic salt) at a concentration of about 0.8 to about 1.5 mol/Lmay be used.

The organic solvent may be, for example, cyclic carbonate esters such aspropylene carbonate, ethylene carbonate, butylene carbonate,chloroethylene carbonate, vinylene carbonate, or the like; cyclic esterssuch as γ-butyrolactone, γ-valero lactone or the like; linear carbonatessuch as dimethyl carbonate, diethylcarbonate, ethylmethyl carbonate, orthe like; linear esters such as methyl formate, methyl acetate, methylbutyrate, or the like; tetrahydrofuran or a derivative thereof; etherssuch as 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxy ethane,1,4-dibutoxyethane, methyl diglyme or the like; nitriles such asacetonitrile, benzonitrile, or the like; dioxolane or a derivativethereof; ethylene sulfide, sulfolane, sultone or a derivative thereofwhich may be used by itself or as a mixture of two or more, withoutlimitation.

A non-aqueous electrolyte solution is impregnated into the belt-shapedseparator 20. On the other hand, each electrode may appropriatelyinclude a known auxiliary conductive agent, an additive, or the like.The exterior material may be, for example, aluminum laminate.

2. Method of Preparing Non-Aqueous Electrolyte Rechargeable Lithium IonBattery

A method of preparing a Non-aqueous electrolyte rechargeable lithium ionbattery is illustrated.

Method of Preparing a Belt-Shaped Positive Electrode

The belt-shaped positive electrode 30 may be, for example, prepared inthe following method.

A positive active material layer material is dispersed in an organicsolvent or water to prepare positive active material layer slurry, andthe positive active material layer slurry is coated on a currentcollector to form a coating layer.

Subsequently, the coating layer is dried and then, compressed with apositive electrode current collector 30 b, preparing the belt-shapedpositive electrode 30.

Method of Preparing a Belt-shaped Negative Electrode

The belt-shaped negative electrode 10 may be, for example, prepared inthe following method.

A negative active material layer material is dispersed in water toprepare negative active material layer slurry, and this negative activematerial layer slurry is coated on a current collector to form a coatinglayer. Subsequently, the coating layer is dried. The fluorine resinparticulate and the elastomer-based polymer particulate in the negativeactive material layer slurry are dispersed in a negative active materiallayer 10 a. Subsequently, the dried coating layer is compressed with anegative current collector 10 b, preparing the belt-shaped negativeelectrode 10.

Method of Preparing a Belt-Shaped Separator

The belt-shaped separator 20 may be prepared in the following method.

A material for an adhesive layer 20 a is dispersed in and dissolved inwater, preparing adhesive layer mix slurry. Subsequently, this adhesivelayer mix slurry is coated on at least one surface of a belt-shapedporous layer 20 c to form a coating layer. Then, this coating layer isdried, forming the adhesive layer 20 a. In other words, the belt-shapedseparator 20 is obtained.

Method of Preparing Wound Element and Battery

The belt-shaped negative electrode 10, the belt-shaped separator 20, thebelt-shaped positive electrode 30, and the belt-shaped separator 20 aresequentially stacked, preparing the electrode stack structure 100 a.Subsequently, the electrode stack structure 100 a is wound. Accordingly,one surface of the electrode stack structure 100 a (i.e., thebelt-shaped separator 20) contacts the other surface of the electrodestack structure 100 a (i.e., the belt-shaped negative electrode 10).Through this process, the wound element 100 is prepared.

Subsequently, the wound element 100 is pushed down to make it flat. Theflat wound element 100 is inserted into an exterior material (forexample, a laminate film) with a non-aqueous electrolyte, and theexterior material is sealed, preparing a rechargeable lithium ionbattery. In one embodiment, when the exterior material is sealed, aterminal end connected to each current collector is protruded out of theexterior material.

Hereinafter, examples and comparative examples of the present inventionare described. These examples, however, are not in any sense to beinterpreted as limiting the scope of the invention.

Example 1 Preparation of Positive Electrode

Lithium cobalt oxide, carbon black, and polyvinylidene fluoride (PVDF)in a solid weight ratio of 96:2:2 were dissolved in and dispersed inN-methyl pyrrolidone, preparing positive active material layer slurry.

The positive active material layer slurry was coated on both sides of a12 μm-thick aluminum foil as a current collector, dried, and compressed,forming a positive active material layer. The current collector and thepositive active material layer had a total thickness of 120 μm.Subsequently, an aluminum lead wire was welded at the terminal end ofthe electrode, obtaining a belt-shaped positive electrode.

Preparation of Negative Electrode

On the other hand, negative active material layer slurry was prepared bydissolving and dispersing graphite, a modified SBR particulate aqueousdispersed material, a fluorine resin-containing particulate aqueousdispersed material complicated by polymerizing an acrylic resin inpolyvinylidene fluoride aqueous dispersed material, and a sodium salt ofcarboxylmethyl cellulose in a solid weight ratio of 97:1:1:1 in and intowater as a solvent. Subsequently, this negative active material layerslurry was coated on both sides of a 10 μm-thick copper foil as acurrent collector and dried.

The dried negative active material layer slurry coating layer wascompressed, forming a negative active material layer. The currentcollector and the negative active material layer had a total thicknessof 120 μm. Then, a nickel lead wire was welded at the terminal end,preparing a belt-shaped negative electrode.

The fluorine resin-containing particulate had an average particlediameter of about 300 nm when measured in a laser diffraction method. Inaddition, when the fluorine resin-containing particulate was examinedwith SEM, it turned out to be a spherical shape particle.

Preparation of Separator

The fluorine resin-containing particulate aqueous dispersed material,poly-N-vinyl acetamide (PNVA), carboxylic acid-modified polybutylacrylate aqueous dispersed material, a cross-linked polystyrene (PS)particle, and an alumina particle having an average particle diameter of0.5 μm were dissolved in and dispersed in water as a solvent, preparingadhesive layer mix slurry.

Herein, the poly-N-vinyl acetamide and the carboxylic acid-modifiedpolybutyl acrylate as a binder for an adhesive layer were mixed in aratio (a mass ratio) of 10:50. In addition, the cross-linked polystyreneparticle and the alumina particle as a heat resistance filler were usedin a volume ratio of 80:20. The fluorine resin-containing particulate,the binder for an adhesive layer, and the heat resistance filler wereused in a volume ratio of 44:6:50. On the other hand, the aluminaparticle had an average particle diameter of 0.5 μm in Example 1 andeach post-described Example and Comparative Example.

Subsequently, the adhesive layer mix slurry was coated on both sides ofa 12 μm-thick corona-treated porous polyethylene separator film anddried, preparing a separator having a 3 μm-thick adhesive layers 20 a atboth sides.

Preparation of Wound Element

The negative electrode, the separator, the positive electrode, and theseparator were stacked in order and wound in a length direction by usinga wick having a diameter of 3 cm. After fixing the end with a tape, thewick was removed, and the cylindrical electrode wound element was put intwo sheets of 3 cm-thick metal plate and maintained for 3 seconds,preparing a flat electrode wound element.

Evaluation of Thickness Increase Ratio

The obtained electrode wound element was allowed to stand for 48 hours,and its thickness increase ratio before and after 48 hours was measuredto evaluate shape stability. Herein, a smaller thickness increase ratioindicates satisfactory shape stability (i.e., a wound element is alittle distorted). The thickness increase ratio was obtained by dividingthe increased thickness of a device before and after allowed to standfor 48 hours by the thickness of the device before allowed to stand.

Preparation of Battery Cell

A battery cell was prepared by sealing the electrode wound element withan electrolyte solution under a reduced pressure with two lead wires outby using a laminate film consisting of threepolypropylene/aluminum/nylon layers. The electrolyte solution wasprepared by preparing ethylene carbonate/ethyl methyl carbonate in avolume ratio of 3:7 and dissolving 1 M LiPF₆ in the mixed solvent. Thebattery cell was inserted between two sheets of 3 cm-thick metal plateheated at 90° C. for 5 minutes.

The obtained battery cell was constant current charged up to 4.4 V with1/10CA of design capacity (1CA is a one hour discharge rate) andconstant voltage charged at 4.4 V up to 1/20 CA. Then, the cell wasconstant current discharged with ½CA down to 3.0 V. In addition, thecapacity of the cell at that moment was regarded as initial dischargecapacity.

Cycle-Life Test

A cycle test was performed by repetitively constant current charging thecell at 0.5 CA and 4.4 V and constant voltage charging it up to 0.05 CAas a charge process and discharging it at 0.5 CA and 3.0 V, and itsdischarge capacity decrease rate (a retention rate) after 100 cyclesbased on the initial discharge capacity was measured to evaluatecycle-life performance. As the discharge capacity decrease rate issmaller, cycle-life characteristics are more excellent. The retentionrate was obtained by dividing the discharge capacity after 100 cycles bythe initial discharge capacity.

Cycle Expansion

The thickness of the prepared battery cell after measuring its initialdischarge capacity was measured as an initial thickness, and the cellwas 100 times repetitively ½ CA low current charged, 1/20 CA low voltagecharged, and ½ CA constant current discharged in order at 4.4 V and 25°C. Then, the thickness of the battery cell was measured and used withthe initial thickness to calculate a variation ratio. As an expansionratio is smaller, the battery cell may have more excellent dimensionalstability. In addition, as the expansion ratio is smaller, an adhesivelayer may have larger adherence.

Adherence Evaluation by Bending Test

After measuring initial discharge capacity of the battery cell, itsbending strength (bending resistance was measured by using a table-topuniversal testing machine, AGS-X made by Shimadzu Co.

The bending strength was measured by mounting the battery cell on a jighaving a gap of 15 mm and disposing an indenter having a curvature witha gap diameter of 2 mmy and a width of 30 mm parallel to the woundelement. Then, a load applied to the cell was measured, while theindenter was pushed down at 1 mm/min, and the maximum value of the loadwas regarded as a bending point, obtaining bending strength. The bendingstrength experiment was performed according to the same method as donefor a cell prepared in the same method as Example 1 except for using anuncoated polyethylene porous film having no adhesive layer as aseparator as a standard battery cell. The maximum load of this standardbattery cell was measured.

Subsequently, the same experiment was performed regarding the batterycell of Example 1 to measure its maximum load. When the obtained maximumload is less than 150% of the standard maximum load, the cell isclassified as x, while the obtained maximum load is greater than orequal to 150% to less than 250%, the cell is classified as Δ, and whengreater than or equal to 250%, the cell is classified as ø.

Example 2

The adhesive layer mix slurry was prepared by dissolving and dispersingthe fluorine resin-containing particulate aqueous dispersed material ofExample 1, poly-N-vinyl acetamide, a cross-linked polymethylmethacrylate particle (PMMA), and a boehmite particle in and intowater as a solvent. Herein, the poly-N-vinyl acetamide is a binder foran adhesive layer. In addition, the cross-linked poly methylmethacrylateparticle and the boehmite particle are a heat resistance filler. Thecross-linked poly methylmethacrylate particle and the boehmite particleare mixed in a volume ratio of 50:50. In addition, the fluorineresin-containing particulate, the binder for an adhesive layer, and theheat resistance filler were mixed in a volume ratio of 45:4:51. Then, abattery cell was prepared according to the same method as Example 1except for using the adhesive layer mix slurry.

Example 3

The fluorine resin-containing particulate aqueous dispersed materialaccording to Example 1, polyvinylpyrrolidone, carboxylic acid-modifiedpolybutyl acrylate, a cross-linked poly methylmethacrylate particle, andan alumina particle were dissolved and dispersed in and into water as asolvent, preparing adhesive layer mix slurry. Herein, thepolyvinylpyrrolidone and the carboxylic acid-modified butyl acrylatewere mixed in a ratio of 1:5 as a binder for an adhesive layer. Inaddition, the cross-linked poly methylmethacrylate particle and thealumina particle were mixed in a volume ratio of 30:70 as a heatresistance filler. Furthermore, the fluorine resin-containingparticulate, the binder for an adhesive layer, and the heat resistancefiller were mixed in a volume ratio of 44:6:50. A battery cell wasprepared according to the same method as Example 1 except for using theadhesive layer mix slurry.

Example 4

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, polyvinyl alcohol and a cross-linked polystyrene particlewere dissolved and dispersed in and into water as a solvent, preparingadhesive layer mix slurry. Herein, the polyvinyl alcohol was a binderfor an adhesive layer, and the cross-linked polystyrene particle was aheat resistance filler. The fluorine resin-containing particulate, thebinder for an adhesive layer, and the heat resistance filler were mixedin a volume ratio of 45:4:51. A battery cell was prepared according tothe same method as Example 1 except for using the adhesive layer mixslurry.

Example 5

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, poly-N-vinyl acetamide, and carboxylic acid-modified butylacrylate was dissolved and dispersed in and into water as a solvent,preparing adhesive layer mix slurry. Herein, the poly-N-vinyl acetamideand the carboxylic acid-modified butyl acrylate were mixed in a ratio of1:5 as a binder for an adhesive layer. In addition, the fluorineresin-containing particulate and the binder for an adhesive layer weremixed in a volume ratio of 93:7. A battery cell was prepared accordingto the same method as Example 1 except for using the adhesive layer mixslurry.

Example 6

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, poly-N-vinyl acetamide, non-modified poly methylmethacrylate,a cross-linked polystyrene particle, and a boehmite particle weredissolved and dispersed in and into water, preparing adhesive layer mixslurry. Herein, the poly-N-vinyl acetamide and the non-modified SBR weremixed in a ratio of 1:4 as a binder for an adhesive layer. In addition,the cross-linked polystyrene particle and the boehmite particle weremixed in a volume ratio of 25:75 as a heat resistance filler.Furthermore, the fluorine resin-containing particulate, the binder foran adhesive layer, and the heat resistance filler were mixed in a volumeratio of 44:6:50. A battery cell was prepared according to the samemethod as Example 1 except for using the adhesive layer mix slurry.

Example 7

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, polyvinyl alcohol, a polyethylene ionomer aqueous dispersedmaterial, and an alumina particle were dissolved in and dispersed inwater as a solvent, preparing adhesive layer mix slurry. Herein, thepolyvinyl alcohol and the polyethylene ionomer were mixed in a ratio of1:5 as a binder for an adhesive layer. In addition, the alumina particlewas a heat resistance filler. Furthermore, the fluorine resin-containingparticulate, the binder for an adhesive layer, and the heat resistancefiller were mixed in a volume ratio of 44:6:50. A battery cell wasprepared according to the same method as Example 1 except for using theadhesive layer mix slurry.

Example 8

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, polyvinyl alcohol, a sodium salt of carboxylmethyl cellulose(CMC-Na), a carboxylic acid-modified polybutyl acrylate aqueousdispersed material, a cross-linked polymethyl methacrylate particle, anda boehmite particle were dissolved in and dispersed in water as asolvent, preparing adhesive layer mix slurry.

The polyvinyl alcohol, the sodium salt of carboxylmethyl cellulose, andthe carboxylic acid-modified polybutyl acrylate were binders for anadhesive layer. The polyvinylpyrrolidone, the sodium salt ofcarboxylmethyl cellulose, and the carboxylic acid-modified polybutylacrylate were mixed in a weight ratio of 45:10:5.

In addition, the cross-linked polymethyl methacrylate particle and theboehmite particle were mixed in a volume ratio of 50:50 as a heatresistance filler. Furthermore, the fluorine resin-containingparticulate, the binder for an adhesive layer, and the heat resistancefiller were mixed in a volume ratio of 44:6:50. Herein, the ionicwater-soluble binder was used in an amount of 0.7 wt % based on theamount of the fluorine resin-containing particulate.

The adhesive layer mix slurry was used to prepare a battery cellaccording to the same method as Example 1.

Comparative Example 1

A separator was prepared by dissolving polyvinylidene fluoride inN-methyl pyrrolidone, coating the solution on both sides of 12 μm-thickporous polyethylene film, dipping the coated film in water, and dryingit to form a mesh-type porous adhesive layer on both sides of the film.Herein, the adhesive layer was 3 μm thick. This separator was usedaccording to the same method as Example 1, preparing a battery cell.

Comparative Example 2

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, carboxylic acid-modified polybutyl acrylate, sodium polyacrylate, and an alumina particle were dissolved in and dispersed inwater as a solvent, preparing adhesive layer mix slurry. Herein, thecarboxylic acid-modified butyl acrylate and the poly acrylic acid weremixed in a mass ratio of 1:5 as a binder for an adhesive layer. Thealumina particle was a heat resistance filler. The fluorineresin-containing particulate, the binder for an adhesive layer, and theheat resistance filler were mixed in a volume ratio of 44:6:50. Theionic water-soluble binder of poly acrylic acid sodium was included inan amount of 2.3 wt % based on the amount of the fluorineresin-containing particulate. The adhesive layer mix slurry was used toprepare a battery cell according to the same method as Example 1.

Comparative Example 3

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, a sodium salt of an isobutylene maleic acid copolymer, and analumina particle were dissolved in and dispersed in water as a solvent,preparing adhesive layer mix slurry. The sodium salt of an isobutylenemaleic acid copolymer was a binder for an adhesive layer. In addition,the alumina particle was a heat resistance filler. The fluorineresin-containing particulate, the binder for an adhesive layer, and theheat resistance filler were mixed in a volume ratio of 45:4:51. Theionic water-soluble binder, the sodium salt of an isobutylene maleicacid copolymer, was used in an amount of 8.9 wt % based on the amount ofthe fluorine resin-containing particulate.

The adhesive layer mix slurry was used to prepare a battery cellaccording to the same method as Example 1.

Comparative Example 4

The fluorine resin-containing particulate aqueous dispersed material ofExample 1, polyvinyl alcohol, a sodium salt of carboxylmethyl cellulose,and an alumina particle was dissolved in and dispersed in water as asolvent, preparing adhesive layer mix slurry. The polyvinyl alcohol andthe sodium salt of carboxylmethyl cellulose were a binder for anadhesive layer. The polyvinyl alcohol and the sodium salt ofcarboxylmethyl cellulose were mixed in a mass ratio of 1:1. In addition,the alumina particle was a heat resistance filler. The fluorineresin-containing particulate, the binder for an adhesive layer, and theheat resistance filler were mixed in a volume ratio of 45:4:51. Thecarboxylmethyl cellulose sodium salt as an ionic water-soluble binderwas used in an amount of 4.4 wt % based on the amount of the fluorineresin-containing particulate.

The adhesive layer mix slurry was used to prepare a battery cellaccording to the same method as Example 1.

Evaluation

The structures of the separators according to Examples 1 to 5 andComparative Examples 1 to 4 were provided in Table 1, and theirevaluation results are provided in Table 2.

TABLE 1 Presence of fluorine Binder 1 resin- (non- Binder 3 Binder 4containing ionic Binder 2 (ionic non- (non-ionic particulate water-(ionic water- water- non-water- Filler 1 Filler 2 in separator soluble)soluble) soluble) soluble) (Organic) (Inorganic) Example 1 Yes PNVA —carboxylic — cross- alumina acid- linked PS modified polybutyl acrylateExample 2 Yes PNVA — — — cross- boehmite linked PMMA Example 3 Yes PVP —carboxylic — cross- alumina acid- linked modified PMMA polybutylacrylate Example 4 Yes PVA — — — cross- — linked PS Example 5 Yes PNVA —carboxylic — — — acid- modified polybutyl acrylate Example 6 Yes PNVA —— Unmodified cross- boehmite PMMA linked PS Example 7 Yes PVA —polyethylene — — alumina ionomer Example 8 Yes PVP CMC—Na carboxylic —cross- boehmite (1.5 wt %) acid- linked modified PMMA polybutyl acrylateComparative No — — — — — — Example 1 Comparative Yes — sodium carboxylic— — alumina Example 2 polyacrylate acid- (5.0 wt %) modified butylacrylate Comparative Yes — Sodium salt — — — alumina Example 3 ofisobutylene maleic acid copolymer Comparative Yes PVA CMC—Na — — —alumina Example 4

TABLE 2 Thickness Cycle increase Cycle- expansion ratio (%) life (%)Adherence (%) Example 1 5 92 ◯ 5 Example 2 5 93 ◯ 6 Example 3 6 92 ◯ 5Example 4 7 91 ◯ 7 Example 5 7 91 ◯ 5 Example 6 5 93 Δ 8 Example 7 5 93◯ 5 Example 8 6 92 ◯ 6 Comparative 10 85 ◯ 7 Example 1 Comparative 6 91X 11 Example 2 Comparative 6 91 X 12 Example 3 Comparative 6 90 X 12Example 4

As shown in Table 2, the battery cells according to Examples 1 to 8 allhad a small thickness increase ratio and a satisfactory cycle-life. Inaddition, the battery cells according to Examples 1 to 8 showedsatisfactory adherence and small cycle expansion. On the other hand, thebattery cell according to Comparative Example 1 was more deformed thanthe battery cells according to Examples 1 to 5, since a fluorineresin-containing polymer had a mesh structure rather than a particlephase and thus deteriorated shape stability of a flat-type woundelement.

In addition, the battery cell of Comparative Example 1 showeddeteriorated cycle-life, and the reason is that the flat-type woundelement was deformed. In other words, since the belt-shaped separator ofComparative Example 1 was less slippery than the belt-shaped separatorsaccording to Examples 1 to 8, and not well slipped at the contact sidesof the electrode stack structure when a wound element was formed to beflat, the electrode wound element was deformed. The battery cellsaccording to Comparative Examples 2 to 4 showed deteriorated adherenceand increased cycle expansion. In Comparative Examples 2, 3, and 4, theionic water-soluble binder was included in an amount of greater than 2.0wt % based on the amount of fluorine resin-containing particulate andthus showed deteriorated adherence and increased cycle expansion.

As a result, the wound elements according to Examples 1 to 8 wereprepared by using a separator easily handled in a preparing process andalso, suppressed from deformation and improved cycle-life of anon-aqueous electrolyte rechargeable battery. In addition, the adherenceof the wound elements was improved, and cycle expansion was improved.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive. Thedisclosure is not limited to the disclosed embodiments. Variations tothe disclosed embodiments can be understood and effected by thoseskilled in the art in practicing the claimed disclosure, from a study ofthe drawings, the disclosure and the appended claims.

All references cited herein are incorporated herein by reference intheir entirety. To the extent publications and patents or patentapplications incorporated by reference contradict the disclosurecontained in the specification, the specification is intended tosupersede and/or take precedence over any such contradictory material.

Unless otherwise defined, all terms (including technical and scientificterms) are to be given their ordinary and customary meaning to a personof ordinary skill in the art, and are not to be limited to a special orcustomized meaning unless expressly so defined herein. It should benoted that the use of particular terminology when describing certainfeatures or aspects of the disclosure should not be taken to imply thatthe terminology is being re-defined herein to be restricted to includeany specific characteristics of the features or aspects of thedisclosure with which that terminology is associated. Terms and phrasesused in this application, and variations thereof, especially in theappended claims, unless otherwise expressly stated, should be construedas open ended as opposed to limiting. As examples of the foregoing, theterm ‘including’ should be read to mean ‘including, without limitation,’‘including but not limited to,’ or the like; the term ‘comprising’ asused herein is synonymous with ‘including,’ ‘containing,’ or‘characterized by,’ and is inclusive or open-ended and does not excludeadditional, unrecited elements or method steps; the term ‘having’ shouldbe interpreted as ‘having at least;’ the term ‘includes’ should beinterpreted as ‘includes but is not limited to;’ the term ‘example’ isused to provide exemplary instances of the item in discussion, not anexhaustive or limiting list thereof; adjectives such as ‘known’,‘normal’, ‘standard’, and terms of similar meaning should not beconstrued as limiting the item described to a given time period or to anitem available as of a given time, but instead should be read toencompass known, normal, or standard technologies that may be availableor known now or at any time in the future; and use of terms like‘preferably,’ ‘preferred,’ ‘desired,’ or ‘desirable,’ and words ofsimilar meaning should not be understood as implying that certainfeatures are critical, essential, or even important to the structure orfunction of the invention, but instead as merely intended to highlightalternative or additional features that may or may not be utilized in aparticular embodiment of the invention. Likewise, a group of itemslinked with the conjunction ‘and’ should not be read as requiring thateach and every one of those items be present in the grouping, but rathershould be read as ‘and/or’ unless expressly stated otherwise. Similarly,a group of items linked with the conjunction ‘or’ should not be read asrequiring mutual exclusivity among that group, but rather should be readas ‘and/or’ unless expressly stated otherwise.

Where a range of values is provided, it is understood that the upper andlower limit, and each intervening value between the upper and lowerlimit of the range is encompassed within the embodiments.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity. The indefinite article “a” or “an” does not exclude aplurality. A single processor or other unit may fulfill the functions ofseveral items recited in the claims. The mere fact that certain measuresare recited in mutually different dependent claims does not indicatethat a combination of these measures cannot be used to advantage. Anyreference signs in the claims should not be construed as limiting thescope.

It will be further understood by those within the art that if a specificnumber of an introduced claim recitation is intended, such an intentwill be explicitly recited in the claim, and in the absence of suchrecitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

All numbers expressing quantities of ingredients, reaction conditions,and so forth used in the specification are to be understood as beingmodified in all instances by the term ‘about.’ Accordingly, unlessindicated to the contrary, the numerical parameters set forth herein areapproximations that may vary depending upon the desired propertiessought to be obtained. At the very least, and not as an attempt to limitthe application of the doctrine of equivalents to the scope of anyclaims in any application claiming priority to the present application,each numerical parameter should be construed in light of the number ofsignificant digits and ordinary rounding approaches.

Furthermore, although the foregoing has been described in some detail byway of illustrations and examples for purposes of clarity andunderstanding, it is apparent to those skilled in the art that certainchanges and modifications may be practiced. Therefore, the descriptionand examples should not be construed as limiting the scope of theinvention to the specific embodiments and examples described herein, butrather to also cover all modification and alternatives coming with thetrue scope and spirit of the invention.

What is claimed is:
 1. An electrode wound element for a non-aqueouselectrolyte rechargeable battery, comprising a belt-shaped positiveelectrode; a belt-shaped negative electrode; a belt-shaped porous layerbetween the belt-shaped positive electrode and the belt-shaped negativeelectrode; and an adhesive layer formed on a surface of the belt-shapedporous layer, wherein the adhesive layer comprises a fluorineresin-containing particulate and a binder for the adhesive layersupporting the fluorine resin-containing particulate and having a totalvolume which is less than that of the fluorine resin-containingparticulate, the binder for the adhesive layer comprising at least onemember selected from the group consisting of an ionic non-water-solublebinder, a non-ionic water-soluble binder, a non-ionic non-water-solublebinder and an ionic water-soluble binder, provided that when the binderfor the adhesive layer comprises an ionic water-soluble binder, thebinder for the adhesive layer further comprises at least one memberselected from the group consisting of an ionic non-water-soluble binder,an non-ionic water-soluble binder and a non-ionic non-water-solublebinder, and wherein a content of the ionic water-soluble binder is about2 wt % or less based on a weight of the fluorine resin-containingparticulate.
 2. The electrode wound element of claim 1, wherein thebinder for the adhesive layer comprises at least one member selectedfrom the group consisting of an ionic non-water-soluble binder and anon-ionic water-soluble binder.
 3. The electrode wound element of claim1, wherein the ionic non-water-soluble binder comprises at least onemember selected from the group consisting of a carboxylic acid-modifiedacrylic acid ester, a polyolefin ionomer, and a carboxylic acid-modifiedstyrene-butadiene copolymer.
 4. The electrode wound element of claim 1,wherein the non-ionic water-soluble binder comprises at least one memberselected from the group consisting of poly-N-vinyl acetamide, polyvinylalcohol, hydroxyethyl cellulose, methyl cellulose, polyvinylpyrrolidone,and polyoxyethylene.
 5. The electrode wound element of claim 1, whereinthe belt-shaped negative electrode comprises a negative active materiallayer comprising a negative active material and a fluorineresin-containing particulate, and wherein the adhesive layer is attachedto the negative active material layer.
 6. The electrode wound element ofclaim 1, wherein the fluorine resin-containing particulate is aspherical-shaped particle.
 7. The electrode wound element of claim 1,wherein the fluorine resin comprises polyvinylidene fluoride.
 8. Anon-aqueous electrolyte rechargeable battery comprising the electrodewound element of claim
 1. 9. A method of preparing an electrode woundelement for a non-aqueous electrolyte rechargeable battery comprising:Coating an aqueous slurry on a surface of a belt-shaped porous layer,the aqueous slurry comprising a fluorine resin-containing particulateand a binder for an adhesive layer supporting the fluorineresin-containing particulate and having a total volume which is lessthan that of the fluorine resin-containing particulate, wherein thebinder for the adhesive layer comprises at least one member selectedfrom the group consisting of an ionic non-water-soluble binder, anon-ionic water-soluble binder, a non-ionic non-water-soluble binder andan ionic water-soluble binder or the binder for an adhesive layerincludes an ionic water-soluble binder and at least one member selectedfrom the group consisting of an ionic non-water-soluble binder, anon-ionic water-soluble binder and a non-ionic non-water-soluble binder,wherein a content of the ionic water-soluble binder is about 2 wt % orless based on the weight of the fluorine resin-containing particulate;and drying the belt-shaped porous layer coated with the aqueous slurry,whereby the electrode wound element of claim 1 is obtained.